DESCRIPTION (Applicant's Abstract): There has been a dearth of psychosocial study in the area HIV vaccine development. Therefore, a clear understanding of what roles psychological processes may play in the development and administration of potential vaccines is lacking. The vaccine research that is currently being done employs HIV-negative volunteers as participants. Research by Sheon (1996) suggests that there are many reasons why volunteers agree to participate in these trials (e.g. altruism, desire for protection, etc.), but there is no clear understanding of how there motives are related to traditional psychological concepts and models. Likewise, there has been concern raised that volunteers who participate in these trials may feel protected from HIV infection and my therefore be less inclined to practice HIV preventive behavior. The purpose of the proposed project is to explore the inter- relationships among personality variables as formulated in the Five Factor Model motivation for vaccine trial participation, protection motivation theory factors (i.e. self-efficacy, perceived risk, perceived thread); and HIV risk behaviors. The candidate proposes that a better knowledge of these relationships is instrumental in providing vaccine researchers with greater understanding of how potential vaccines are perceived and a clearer notion of who is participating in these trials, their reasons for volunteering, and how these factors relate to risk behavior.